Space surveillance shows that the ground beneath our feet is not quite as solid as it seems. Earth’s crust is continuously in motion, driven by gradual geological shifting that occasionally speeds up, in the potentially destructive form of earthquakes or volcanoes.

Looking down on Earth from hundreds of kilometres away in space has proven a surprisingly accurate way of detecting slight sub-centimetre-scale motion across tens of kilometres of terrain that might otherwise go unobserved.

Combining together multiple radar images of the same location through a technique called Synthetic Aperture Radar Interferometry highlights tiny land changes that have occurred between acquisitions. It’s a technique that has been used to survey the seismically active belts that make up around 15% of global land area, in order to search out previously unknown fault lines.

InSAR has also been used to survey supposedly extinct volcanoes – slight signs of ‘breathing’ indicate continued active status.

04 August 2017

A magnitude 6.6 earthquake occurred in the Aegean Sea on 20 July 2017, affecting the Greek island of Kos and Bodrum in south-west Turkey. Images from the Copernicus Sentinel-1 mission were used to map the ground deformation, providing valuable data for analysis.

The use of satellite data in the detailed study and precise
measurement of the Earth's geoid in order to improve our
understanding both of the Earth's interior, and dynamic topography
of the world's oceans.

Observations show that geomagnetic field lines follow closely the
atmospheric circulation patterns and that geomagnetic field
variations are precursors to climate change. Therefore close
monitoring of the local and global geomagnetic field variations by
satellite systems will assist prediction of hurricane tracks,
intensification and also long-term weather trends.

The monitoring of the movement and deformation of the Earth's crust
with the aim of understanding its evolution and of predicting major
seismic events. Interferometry is an important technique in this
application.